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Boring Company Selected to Build O’Hare Express in Chicago.
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Singer3000
Member
I don’t dispute that it could be quite pleasant to ride on this system, especially if it only cost me the price of a latte. In fact I’d like a lift from my bedroom down to a station in my basement that gets me home from the pub. The bit I haven’t wrapped my head around yet is how a few interns with some senior engineer oversight can in one year, disrupt the cost so much that sort of thing would be possible at the claimed cost. TBMs are pretty well established tech.
Tesla moving away from ICE to electric, obvious disruption; SpaceX drastically improving reusability, obvious disruption. All I’m seeing here is a narrower diameter (with far less capacity as a result), a boast that “we’ll use more power in the drilling” and a yet to be proven idea to commercially reuse the spoil to recoup some cost. Batteries in the vehicles is nice but again, not really a new paradigm in the train industry, albeit not yet done at scale.
Tesla moving away from ICE to electric, obvious disruption; SpaceX drastically improving reusability, obvious disruption. All I’m seeing here is a narrower diameter (with far less capacity as a result), a boast that “we’ll use more power in the drilling” and a yet to be proven idea to commercially reuse the spoil to recoup some cost. Batteries in the vehicles is nice but again, not really a new paradigm in the train industry, albeit not yet done at scale.
WannabeOwner
Well-Known Member
I think its the same as EVs. Established companies reluctant to bet-the-farm, so stick to ICE and small incremental improvements. This is a $1b bet.
Tesla has the Skate [mostly], so is adding value to model-X. Existing companies don't (didn't) have any suitable rolling stock for a narrow bore tunnel, or their napkin-maths didn't suggest it was worthwhile.
NASA didn't make re-landable rockets. Some Space-X engineers have figured that out and become disruptive as a result. Setting the Boring engineers a goal of "tunnel faster & cheaper" seems reasonable; but that then requires an R&D budget to achieve that ... and again maybe established companies haven't wanted to do that ... complacent / conservative ...
... I doubt Boring Company are short of CVs from the best, relevant, engineers on the planet right now ... including some with brilliant ideas frustrated by lack of opportunity / R&D $$$ at their current employer.
Singer3000
Member
Hmmm... Anyone know the market share split of TBM manufacturing right now? If this is true, how is it that’s about to get disrupted and what’s at stake?
- Internalizing design and manufacturing of TBM (no mark up)
- Internalized everything else (no 2rd/3rd/4th parties with mark up)
- Lower cost TBM and reuse (more TBM working simultaneously [start two at middle of tunnel digging toward the ends])
- Battery powered automated muck carts (less time setting up infrastructure, less ventilation requirement, less labor cost)
- Electric TBM (less ventilation requirenents), lower energy costs
- Higher force/ rotational rate at cutter head (reduced project time)
- Smaller tunnel (less cost, faster)
- Simultaneous digging and segment placing (major speed increase)
- Automation (higher up time and lower cost)
Singer3000
Member
Thanks for this. I’m no tunnelling engineer but from what I’ve seen/read over the years, quite a bit of this isn’t new. e.g. reuse of TBM, tunnelling from multiple entry points, simultaneous segment placing...
The main selling point seems to be that they can build more quickly with less spoil because its narrower. It’s therefore much lower capacity but the initial ticket prices will reflect this versus a standard metro ticket (did I see $25?). And because no serious effort is being made (at least initially) to make this mass transit, nor are there interim stations, no large expensive underground station boxes are needed. Except the terminus and that’s being provided for free.
The dream of many hundreds of small entry points is a nice one and maybe that will work in a modern recently built city (Gulf states?). But how do you do this in places with complicated layers of utilities, sewerage, foundations and existing metro lines? And even if you succeed, do you not require a monopoly for this to work under a private finance/ownership model? You can’t have 5 companies all drilling in the same places with distinct networks.
In short, it’s hard for me to get excited about this yet. Still feels like the Shanghai maglev - fun to ride but ultimately pointless. Sorry to be a downer, hopefully I’m wrong.
I'm not aware of current TBMs that do simultaneous excavation and placement (but that's not saying much). Current designs seem to have one set of pusher hydraulics that brace off the previous fully installed section of segments. Boring's is likely using a set of pushers twice as long (or two sets with intermediate support ring) so that the head is pushing off both the completed ring and the new/ partial segments, with only the currently being installed section being retracted. Also requires a longer outer surface/ shield due to the cutter head being further forward from the closest complete ring.
Tunnel depth is minimum two diameters 30-40 feet. Utilities are not that deep, and existing rail tunnels can be gone under. Tunnel follow surface streets, so no foundation or purchasing issues. Entry points only require a slightly larger than skate vertical opening between existing utilities. Or connect to existing building basement.
No one else has the new TBM tech, access to electric skates, or desire to make a tunnel system at Boring's price point, so monopoly by default. However, I'm guessing Boring would be happy to supply/ sell machines and cross connect to increase adoption. (Like Tesla and Superchargers)
Hyperloop does have various interested companies, but they may be focusing on above ground implementation.
I would not be surprised if Boring ends up able to install tunnels at a lower price than urban 2 lane roads (5 million a mile) and at a shorter total project time.
Agreed. Traditional companies have little interest or understanding of innovation, they tend to be quite complacent and as such are ripe for the picking. When was the last time you bought a new Polaroid camera?
The depth The Boring Company is talking about is far below most urban infrastructure. In a lot of downtown areas though, I think they will have problems with building pilings, which may require them to run under existing streets which, in turn, will require tight turns in some cases. They may have to go very deep in some cities to get into the bedrock below the building foundations. It will be interesting to see how that works out.
Of course, they could do something like bore right through the pilings, then build reinforced linings in the tunnel there to transfer the weight of the building from the piling above, around the tunnel, and back down to the cut off piling below.
Or, maybe not.
The depth The Boring Company is talking about is far below most urban infrastructure. In a lot of downtown areas though, I think they will have problems with building pilings, which may require them to run under existing streets which, in turn, will require tight turns in some cases. They may have to go very deep in some cities to get into the bedrock below the building foundations. It will be interesting to see how that works out.
Of course, they could do something like bore right through the pilings, then build reinforced linings in the tunnel there to transfer the weight of the building from the piling above, around the tunnel, and back down to the cut off piling below.
Or, maybe not.
WannabeOwner
Well-Known Member
On the face of it, but I wonder if it is significant?
Inter-city trains here are 4 seats across, commuter trains 5 seats (with an awkward / narrow aisle) and subway typically two across (bench seat on each side) with wide aisle for standing. model-X is 3-across, and maybe the skate will be wide enough for 4-across - so, with absence of aisle, or a squeeze-through only, then similar seat density to train (per unit of seating-area-length)
Subway Trains are a minute or two apart, but have all the inconvenience of stopping in stations (and blocking the track), and max speed is 70-80MPH (but rarely sustains) so following train has to slow/stop, or have a significant follow-gap, or stations are evenly spaced so all trains are stop/go to roughly the same extent.
Loop is a single express tunnel, all traffic at full cruising speed (100-150 MPH?) with any slowing down / stopping done on a side-line into the station (when multiple stations exist). So once you have got going you are going to cruise at 100 - 150 MPH all the way until the turn-off for your destination station. Using cars for comparison the follow-distance could be as close as 2 seconds, and the comfortable stopping rate of deceleration, and stopping distance, would be much shorter than a train (which also reduces the "load" that trains transport, where there are multiple stops.
Whilst Trains have multiple carriages, and therefore lots of passengers per train, maybe Skates can achieve similar rates of passengers passing a given point per unit of time?
Currently, simultaneous segment placement is only used in hard rock. The TBM is pushed forward by gripping the hard rock and pushing against it.
The vast majority of TBMs are rather in softer soil and are called Earth Pressure Balance TBMs and do not perform simultaneous segment placement. As far as I know, the TBMs in Chicago would be the first EPB TBMs to do simultaneous segment placement.
From the Q&A video it sounded like they were on their 2nd iteration of TBM (1st being stock), and they had the 3rd version in the works, so I would expect it to be tested before Chicago.
Extra background:
A hard rock TBM does not need to support the tunnel while digging, so it can scoot forward leaving the bare rock surface behind it. Earth pressure type are going though sand or muck, so they have a shield cylinder sealed at the cutting head which slides along the outside of the finished tunnel. Grout is pumped in behind the trailing end of the shield to maintain pressure and provide the final sealing layer for tunnel. The TBM pushes off from the leading edge of the finished tunnel, due to it being the only solid surface.
Extra background:
A hard rock TBM does not need to support the tunnel while digging, so it can scoot forward leaving the bare rock surface behind it. Earth pressure type are going though sand or muck, so they have a shield cylinder sealed at the cutting head which slides along the outside of the finished tunnel. Grout is pumped in behind the trailing end of the shield to maintain pressure and provide the final sealing layer for tunnel. The TBM pushes off from the leading edge of the finished tunnel, due to it being the only solid surface.
Singer3000
Member
Thanks for the share of knowledge everyone. What’s great about this is that the risks and rewards are privatised, hence the motivation to innovate. Too many infrastructure projects rely on a willing payer of last resort (us taxpayers!). All quite ironic because this is not how the original railway industry started at all.
The downside is it can lead to slightly chaotic placement of infrastructure on an overall basis. London has many major stations and lines which are very close but not integrated well if at all, as the legacy from Victorian private sector competition. Not an issue with a single airport shuttle but since this plans seems much grander, that’ll need to be thought about carefully with govt at some point.
The downside is it can lead to slightly chaotic placement of infrastructure on an overall basis. London has many major stations and lines which are very close but not integrated well if at all, as the legacy from Victorian private sector competition. Not an issue with a single airport shuttle but since this plans seems much grander, that’ll need to be thought about carefully with govt at some point.
In the US there was massive government support for the national rail system, mainly through land giveaways (about 10% of the entire land area of the US) and very low cost loans. Without those, it's doubtful that the transcontinental rail system would have existed for decades.
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